/*
 * arch/sh/kernel/cpu/clock.c - SuperH clock framework
 *
 *  Copyright (C) 2005 - 2009  Paul Mundt
 *
 * This clock framework is derived from the OMAP version by:
 *
 *      Copyright (C) 2004 - 2008 Nokia Corporation
 *      Written by Tuukka Tikkanen <tuukka.tikkanen@elektrobit.com>
 *
 *  Modified for omap shared clock framework by Tony Lindgren <tony@atomide.com>
 *
 *  With clkdev bits:
 *
 *      Copyright (C) 2008 Russell King.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/kobject.h>
#include <linux/sysdev.h>
#include <linux/seq_file.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/debugfs.h>
#include <linux/cpufreq.h>
#include <asm/clock.h>
#include <asm/machvec.h>

static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);

void clk_rate_table_build(struct clk *clk,
                          struct cpufreq_frequency_table *freq_table,
                          int nr_freqs,
                          struct clk_div_mult_table *src_table,
                          unsigned long *bitmap)
{
        unsigned long mult, div;
        unsigned long freq;
        int i;

        for (i = 0; i < nr_freqs; i++) {
                div = 1;
                mult = 1;

                if (src_table->divisors && i < src_table->nr_divisors)
                        div = src_table->divisors[i];

                if (src_table->multipliers && i < src_table->nr_multipliers)
                        mult = src_table->multipliers[i];

                if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
                        freq = CPUFREQ_ENTRY_INVALID;
                else
                        freq = clk->parent->rate * mult / div;

                freq_table[i].index = i;
                freq_table[i].frequency = freq;
        }

        /* Termination entry */
        freq_table[i].index = i;
        freq_table[i].frequency = CPUFREQ_TABLE_END;
}

long clk_rate_table_round(struct clk *clk,
                          struct cpufreq_frequency_table *freq_table,
                          unsigned long rate)
{
        unsigned long rate_error, rate_error_prev = ~0UL;
        unsigned long rate_best_fit = rate;
        unsigned long highest, lowest;
        int i;

        highest = lowest = 0;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                unsigned long freq = freq_table[i].frequency;

                if (freq == CPUFREQ_ENTRY_INVALID)
                        continue;

                if (freq > highest)
                        highest = freq;
                if (freq < lowest)
                        lowest = freq;

                rate_error = abs(freq - rate);
                if (rate_error < rate_error_prev) {
                        rate_best_fit = freq;
                        rate_error_prev = rate_error;
                }

                if (rate_error == 0)
                        break;
        }

        if (rate >= highest)
                rate_best_fit = highest;
        if (rate <= lowest)
                rate_best_fit = lowest;

        return rate_best_fit;
}

int clk_rate_table_find(struct clk *clk,
                        struct cpufreq_frequency_table *freq_table,
                        unsigned long rate)
{
        int i;

        for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
                unsigned long freq = freq_table[i].frequency;

                if (freq == CPUFREQ_ENTRY_INVALID)
                        continue;

                if (freq == rate)
                        return i;
        }

        return -ENOENT;
}

/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{
        return clk->parent ? clk->parent->rate : 0;
}

int clk_reparent(struct clk *child, struct clk *parent)
{
        list_del_init(&child->sibling);
        if (parent)
                list_add(&child->sibling, &parent->children);
        child->parent = parent;

        /* now do the debugfs renaming to reattach the child
           to the proper parent */

        return 0;
}

/* Propagate rate to children */
void propagate_rate(struct clk *tclk)
{
        struct clk *clkp;

        list_for_each_entry(clkp, &tclk->children, sibling) {
                if (clkp->ops && clkp->ops->recalc)
                        clkp->rate = clkp->ops->recalc(clkp);

                propagate_rate(clkp);
        }
}

static void __clk_disable(struct clk *clk)
{
        if (clk->usecount == 0) {
                printk(KERN_ERR "Trying disable clock %s with 0 usecount\n",
                       clk->name);
                WARN_ON(1);
                return;
        }

        if (!(--clk->usecount)) {
                if (likely(clk->ops && clk->ops->disable))
                        clk->ops->disable(clk);
                if (likely(clk->parent))
                        __clk_disable(clk->parent);
        }
}

void clk_disable(struct clk *clk)
{
        unsigned long flags;

        if (!clk)
                return;

        spin_lock_irqsave(&clock_lock, flags);
        __clk_disable(clk);
        spin_unlock_irqrestore(&clock_lock, flags);
}
EXPORT_SYMBOL_GPL(clk_disable);

static int __clk_enable(struct clk *clk)
{
        int ret = 0;

        if (clk->usecount++ == 0) {
                if (clk->parent) {
                        ret = __clk_enable(clk->parent);
                        if (unlikely(ret))
                                goto err;
                }

                if (clk->ops && clk->ops->enable) {
                        ret = clk->ops->enable(clk);
                        if (ret) {
                                if (clk->parent)
                                        __clk_disable(clk->parent);
                                goto err;
                        }
                }
        }

        return ret;
err:
        clk->usecount--;
        return ret;
}

int clk_enable(struct clk *clk)
{
        unsigned long flags;
        int ret;

        if (!clk)
                return -EINVAL;

        spin_lock_irqsave(&clock_lock, flags);
        ret = __clk_enable(clk);
        spin_unlock_irqrestore(&clock_lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(clk_enable);

static LIST_HEAD(root_clks);

/**
 * recalculate_root_clocks - recalculate and propagate all root clocks
 *
 * Recalculates all root clocks (clocks with no parent), which if the
 * clock's .recalc is set correctly, should also propagate their rates.
 * Called at init.
 */
void recalculate_root_clocks(void)
{
        struct clk *clkp;

        list_for_each_entry(clkp, &root_clks, sibling) {
                if (clkp->ops && clkp->ops->recalc)
                        clkp->rate = clkp->ops->recalc(clkp);
                propagate_rate(clkp);
        }
}

int clk_register(struct clk *clk)
{
        if (clk == NULL || IS_ERR(clk))
                return -EINVAL;

        /*
         * trap out already registered clocks
         */
        if (clk->node.next || clk->node.prev)
                return 0;

        mutex_lock(&clock_list_sem);

        INIT_LIST_HEAD(&clk->children);
        clk->usecount = 0;

        if (clk->parent)
                list_add(&clk->sibling, &clk->parent->children);
        else
                list_add(&clk->sibling, &root_clks);

        list_add(&clk->node, &clock_list);
        if (clk->ops && clk->ops->init)
                clk->ops->init(clk);
        mutex_unlock(&clock_list_sem);

        return 0;
}
EXPORT_SYMBOL_GPL(clk_register);

void clk_unregister(struct clk *clk)
{
        mutex_lock(&clock_list_sem);
        list_del(&clk->sibling);
        list_del(&clk->node);
        mutex_unlock(&clock_list_sem);
}
EXPORT_SYMBOL_GPL(clk_unregister);

static void clk_enable_init_clocks(void)
{
        struct clk *clkp;

        list_for_each_entry(clkp, &clock_list, node)
                if (clkp->flags & CLK_ENABLE_ON_INIT)
                        clk_enable(clkp);
}

unsigned long clk_get_rate(struct clk *clk)
{
        return clk->rate;
}
EXPORT_SYMBOL_GPL(clk_get_rate);

int clk_set_rate(struct clk *clk, unsigned long rate)
{
        return clk_set_rate_ex(clk, rate, 0);
}
EXPORT_SYMBOL_GPL(clk_set_rate);

int clk_set_rate_ex(struct clk *clk, unsigned long rate, int algo_id)
{
        int ret = -EOPNOTSUPP;
        unsigned long flags;

        spin_lock_irqsave(&clock_lock, flags);

        if (likely(clk->ops && clk->ops->set_rate)) {
                ret = clk->ops->set_rate(clk, rate, algo_id);
                if (ret != 0)
                        goto out_unlock;
        } else {
                clk->rate = rate;
                ret = 0;
        }

        if (clk->ops && clk->ops->recalc)
                clk->rate = clk->ops->recalc(clk);

        propagate_rate(clk);

out_unlock:
        spin_unlock_irqrestore(&clock_lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(clk_set_rate_ex);

int clk_set_parent(struct clk *clk, struct clk *parent)
{
        unsigned long flags;
        int ret = -EINVAL;

        if (!parent || !clk)
                return ret;
        if (clk->parent == parent)
                return 0;

        spin_lock_irqsave(&clock_lock, flags);
        if (clk->usecount == 0) {
                if (clk->ops->set_parent)
                        ret = clk->ops->set_parent(clk, parent);
                else
                        ret = clk_reparent(clk, parent);

                if (ret == 0) {
                        pr_debug("clock: set parent of %s to %s (new rate %ld)\n",
                                 clk->name, clk->parent->name, clk->rate);
                        if (clk->ops->recalc)
                                clk->rate = clk->ops->recalc(clk);
                        propagate_rate(clk);
                }
        } else
                ret = -EBUSY;
        spin_unlock_irqrestore(&clock_lock, flags);

        return ret;
}
EXPORT_SYMBOL_GPL(clk_set_parent);

struct clk *clk_get_parent(struct clk *clk)
{
        return clk->parent;
}
EXPORT_SYMBOL_GPL(clk_get_parent);

long clk_round_rate(struct clk *clk, unsigned long rate)
{
        if (likely(clk->ops && clk->ops->round_rate)) {
                unsigned long flags, rounded;

                spin_lock_irqsave(&clock_lock, flags);
                rounded = clk->ops->round_rate(clk, rate);
                spin_unlock_irqrestore(&clock_lock, flags);

                return rounded;
        }

        return clk_get_rate(clk);
}
EXPORT_SYMBOL_GPL(clk_round_rate);

/*
 * Find the correct struct clk for the device and connection ID.
 * We do slightly fuzzy matching here:
 *  An entry with a NULL ID is assumed to be a wildcard.
 *  If an entry has a device ID, it must match
 *  If an entry has a connection ID, it must match
 * Then we take the most specific entry - with the following
 * order of precidence: dev+con > dev only > con only.
 */
static struct clk *clk_find(const char *dev_id, const char *con_id)
{
        struct clk_lookup *p;
        struct clk *clk = NULL;
        int match, best = 0;

        list_for_each_entry(p, &clock_list, node) {
                match = 0;
                if (p->dev_id) {
                        if (!dev_id || strcmp(p->dev_id, dev_id))
                                continue;
                        match += 2;
                }
                if (p->con_id) {
                        if (!con_id || strcmp(p->con_id, con_id))
                                continue;
                        match += 1;
                }
                if (match == 0)
                        continue;

                if (match > best) {
                        clk = p->clk;
                        best = match;
                }
        }
        return clk;
}

struct clk *clk_get_sys(const char *dev_id, const char *con_id)
{
        struct clk *clk;

        mutex_lock(&clock_list_sem);
        clk = clk_find(dev_id, con_id);
        mutex_unlock(&clock_list_sem);

        return clk ? clk : ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL_GPL(clk_get_sys);

/*
 * Returns a clock. Note that we first try to use device id on the bus
 * and clock name. If this fails, we try to use clock name only.
 */
struct clk *clk_get(struct device *dev, const char *id)
{
        const char *dev_id = dev ? dev_name(dev) : NULL;
        struct clk *p, *clk = ERR_PTR(-ENOENT);
        int idno;

        clk = clk_get_sys(dev_id, id);
        if (clk && !IS_ERR(clk))
                return clk;

        if (dev == NULL || dev->bus != &platform_bus_type)
                idno = -1;
        else
                idno = to_platform_device(dev)->id;

        mutex_lock(&clock_list_sem);
        list_for_each_entry(p, &clock_list, node) {
                if (p->id == idno &&
                    strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
                        clk = p;
                        goto found;
                }
        }

        list_for_each_entry(p, &clock_list, node) {
                if (strcmp(id, p->name) == 0 && try_module_get(p->owner)) {
                        clk = p;
                        break;
                }
        }

found:
        mutex_unlock(&clock_list_sem);

        return clk;
}
EXPORT_SYMBOL_GPL(clk_get);

void clk_put(struct clk *clk)
{
        if (clk && !IS_ERR(clk))
                module_put(clk->owner);
}
EXPORT_SYMBOL_GPL(clk_put);

#ifdef CONFIG_PM
static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
{
        static pm_message_t prev_state;
        struct clk *clkp;

        switch (state.event) {
        case PM_EVENT_ON:
                /* Resumeing from hibernation */
                if (prev_state.event != PM_EVENT_FREEZE)
                        break;

                list_for_each_entry(clkp, &clock_list, node) {
                        if (likely(clkp->ops)) {
                                unsigned long rate = clkp->rate;

                                if (likely(clkp->ops->set_parent))
                                        clkp->ops->set_parent(clkp,
                                                clkp->parent);
                                if (likely(clkp->ops->set_rate))
                                        clkp->ops->set_rate(clkp,
                                                rate, NO_CHANGE);
                                else if (likely(clkp->ops->recalc))
                                        clkp->rate = clkp->ops->recalc(clkp);
                        }
                }
                break;
        case PM_EVENT_FREEZE:
                break;
        case PM_EVENT_SUSPEND:
                break;
        }

        prev_state = state;
        return 0;
}

static int clks_sysdev_resume(struct sys_device *dev)
{
        return clks_sysdev_suspend(dev, PMSG_ON);
}

static struct sysdev_class clks_sysdev_class = {
        .name = "clks",
};

static struct sysdev_driver clks_sysdev_driver = {
        .suspend = clks_sysdev_suspend,
        .resume = clks_sysdev_resume,
};

static struct sys_device clks_sysdev_dev = {
        .cls = &clks_sysdev_class,
};

static int __init clk_sysdev_init(void)
{
        sysdev_class_register(&clks_sysdev_class);
        sysdev_driver_register(&clks_sysdev_class, &clks_sysdev_driver);
        sysdev_register(&clks_sysdev_dev);

        return 0;
}
subsys_initcall(clk_sysdev_init);
#endif

int __init clk_init(void)
{
        int ret;

        ret = arch_clk_init();
        if (unlikely(ret)) {
                pr_err("%s: CPU clock registration failed.\n", __func__);
                return ret;
        }

        if (sh_mv.mv_clk_init) {
                ret = sh_mv.mv_clk_init();
                if (unlikely(ret)) {
                        pr_err("%s: machvec clock initialization failed.\n",
                               __func__);
                        return ret;
                }
        }

        /* Kick the child clocks.. */
        recalculate_root_clocks();

        /* Enable the necessary init clocks */
        clk_enable_init_clocks();

        return ret;
}

/*
 *      debugfs support to trace clock tree hierarchy and attributes
 */
static struct dentry *clk_debugfs_root;

static int clk_debugfs_register_one(struct clk *c)
{
        int err;
        struct dentry *d, *child;
        struct clk *pa = c->parent;
        char s[255];
        char *p = s;

        p += sprintf(p, "%s", c->name);
        if (c->id >= 0)
                sprintf(p, ":%d", c->id);
        d = debugfs_create_dir(s, pa ? pa->dentry : clk_debugfs_root);
        if (!d)
                return -ENOMEM;
        c->dentry = d;

        d = debugfs_create_u8("usecount", S_IRUGO, c->dentry, (u8 *)&c->usecount);
        if (!d) {
                err = -ENOMEM;
                goto err_out;
        }
        d = debugfs_create_u32("rate", S_IRUGO, c->dentry, (u32 *)&c->rate);
        if (!d) {
                err = -ENOMEM;
                goto err_out;
        }
        d = debugfs_create_x32("flags", S_IRUGO, c->dentry, (u32 *)&c->flags);
        if (!d) {
                err = -ENOMEM;
                goto err_out;
        }
        return 0;

err_out:
        d = c->dentry;
        list_for_each_entry(child, &d->d_subdirs, d_u.d_child)
                debugfs_remove(child);
        debugfs_remove(c->dentry);
        return err;
}

static int clk_debugfs_register(struct clk *c)
{
        int err;
        struct clk *pa = c->parent;

        if (pa && !pa->dentry) {
                err = clk_debugfs_register(pa);
                if (err)
                        return err;
        }

        if (!c->dentry) {
                err = clk_debugfs_register_one(c);
                if (err)
                        return err;
        }
        return 0;
}

static int __init clk_debugfs_init(void)
{
        struct clk *c;
        struct dentry *d;
        int err;

        d = debugfs_create_dir("clock", NULL);
        if (!d)
                return -ENOMEM;
        clk_debugfs_root = d;

        list_for_each_entry(c, &clock_list, node) {
                err = clk_debugfs_register(c);
                if (err)
                        goto err_out;
        }
        return 0;
err_out:
        debugfs_remove(clk_debugfs_root); /* REVISIT: Cleanup correctly */
        return err;
}
late_initcall(clk_debugfs_init);